Units are deemed “in the Command Chain” if they belong
to an Army which is, in turn, attached to an Army Group (also
sometimes called the GHQ, Great Headquarter). Any Units which
don’t belong to such an Army are considered independent Stacks
for Command Chain purposes, and they have a penalty of -50% to
the Command Points generated by the leaders in that Stack. Naval
Stacks are handled differently without a hierarchy other than Units
and Fleets.
On the map, you can then have three kinds of land Stacks:
• The Army Group (or GHQ) Stack, which is the Stack
commanding subordinate Armies.
• The Army Stack, which is a Stack subordinate to an Army
Group or GHQ Stack.
• Independent Stack, which is a Stack Out of the Command
Chain.
These three Stacks each have Units and they are all “containers”
for Units. Units represent formations of various sizes and act as
“containers” for elements, with from 1 to 9 elements in each Unit.

Some questions: 1) In the very first sentance what does "belong" mean?

2) Pretty sure i'm wrong here but doesn't the above mean a Korps in a region on its own is always an Independent stack? If so they don't seem to be suffering a command penalty, (it still shows as 24 for a 2 star general, and to make matters more confusing the manual says it should be 36).

Sorry to spam all these questions but am trying to understand the mechanics and am beginning to think my biggest mistake was reading the manual :(

1. In the same stack as. If in a separate stack and in the same region it does not belong to the army you need to drop it into the army stack.

2. Need to read the manual before I can help out on this one, I'll take a look.

After reading the manual it is apparent that things have been changed a lot since it was written. Corp commanders seem to be in command at all times now and command point totals in game are different from the manual. A dev will need to chime in on this one, but for now only use the manual as a guide and realize the numbers given in the manual are no longer accurate.

1. "belong" means they are attached to (but not necessarily influenced by) a GHQ. If you click on the army stack, the GHQ will flash on the map. To be influenced by that GHQ, however, they need to be in the GHQ's command radius (click on GHQ and press shift)

2. Corps are always independent. They will, however, act with an Army in the same area (so for example, if you have coordinated move clicked on the army, and then move it, the corps in that area will want to tag along).

Of course, MTSG will influence adjacent independent corps -- this leads to some very large battles when you only wanted a small one. It also means that front lines have mutual support, which is reflective of the war.

2. Corps are always independent. They will, however, act with an Army in the same area (so for example, if you have coordinated move clicked on the army, and then move it, the corps in that area will want to tag along).

Of course, MTSG will influence adjacent independent corps -- this leads to some very large battles when you only wanted a small one. It also means that front lines have mutual support, which is reflective of the war.

Sorry if this seems a stupid question but what's the point of an army if this is the case? I've been playing a few turns with the historical scenario and there doesn't seem to be any particular problem with corps suffering command penalties (apart from the BEF, which is out of the range of its GHQ). It seems to me that, as long as a corps is within the influence of GHQ then armies are superfluous - or am I missing something?

Sorry if this seems a stupid question but what's the point of an army if this is the case? I've been playing a few turns with the historical scenario and there doesn't seem to be any particular problem with corps suffering command penalties (apart from the BEF, which is out of the range of its GHQ). It seems to me that, as long as a corps is within the influence of GHQ then armies are superfluous - or am I missing something?

The main reasons for forming armies are: 1. if in range of the GHQ, the army can get buffs in combat from that GHQ 2. armies can handle many more elements than a simple corps. Corps usually have a command rating of 24 (varies with commander's abilities), but armies are generally over double that. So, you end up with a large stack/force. With good generals, this is very effective for combat.